1. Field of Invention
This invention relates to volleyball, specifically to a portable, lightweight machine that incorporates a mechanical timer and is used to practice volleyball spiking skills by throwing a volleyball into the air.
2. Description of Prior Art
Volleyball is a team sport that requires three basic skills: passing, setting and spiking. A volleyball player must practice these skills often to become proficient. Passing and setting can be done alone; however, spiking requires another person to throw or toss the volleyball into the air so the player can spike it. Several devices have been devised to throw or toss a volleyball. All devices to-date have been large, complicated, heavy, and expensive to manufacture. In addition, most of these devices require electrical power and are not portable.
One such device is shown in U.S. Pat. No. 3,552,371 to Edward W. Kahelin (Jan. 05, 1971). The device is a large assembly consisting of metal braces, support frame, and struts to support a coil spring and throwing arm. This device can not be easily transported to the beach or gymnasium where volleyball practice usually is conducted. Moreover, this device is does not reproduce throw the volleyball in a parabolic trajectory which necessary to simulate the throw/set from a human.
Another device is shown in U.S. Pat. No. 3,605,715 to Dale K. Welborne (Sep. 20, 1971), which uses a coil spring and pivot arm to throw a volleyball in a catapult manner. While this device is portable, is does not provide the ball motion and trajectory necessary to practice spiking a volleyball.
Two other devices have been developed to set a volleyball, and they are shown in U.S. Pat. No. 4,254,755 to Steven R. Morgan and Dwayne E. Reese (Mar. 10, 1981) and U.S. Pat. No. 4,714,069 to Harold C. Ulrich (Dec. 22, 1987). Each of these devices requires electric power and is not easily transported. They are heavy, complicated, and expensive to manufacture.